This invention relates to metal catalyst supports. Such supports comprise metal "skeletons" which are coated with a catalyst, and through which gas is made to travel. The catalyst support must therefore allow the gas to come into contact with the catalyst, but must also allow the gas to flow through the support unimpeded.
My copending Application Ser. No. 894,180 discloses a metal catalyst support in the form of a spiral formed by winding a single strip of metal upon itself, wherein the spacing between layers of the spiral is uniform. The uniform spacing in the spiral is maintained by indentations similar to those in the present flat strips, to be described below. In both types of catalyst supports, it is necessary to prevent the indentations in successive layers or strips from nesting together. In the spiral, this coincidence is prevented by spacing the indentations along the spiral in a pattern that varies, and is not repeated in any layer of the spiral.
A spirally wound metal catalyst support has a cylindrical shape and a circular face. The cylindrical shape is best for catalytic combustors and catalytic mufflers. But if one needs to treat catalytically the flue gas from an electric power plant, the flow of gas is enormous, and so is the cross-sectional area of the catalyst. The large cross section can be filled completely with rectangles, but not with circles. Hence, the preferred metal catalyst support for treating flue gas is a stack of strips having a rectangular face instead of a circular face. Individual stacks of strips, of rectangular shape, are nested together like the panes in a window, as will be described below.